(a) Field of the Invention
The present invention relates to a liquid crystal display and a driving method thereof.
(b) Description of Related Art
A liquid crystal display (LCD) includes an upper panel including a common electrode and a plurality of color filters and covered with an alignment layer, a lower panel including a plurality of thin film transistors and a plurality of pixel electrodes and covered with an alignment layer, and a liquid crystal layer interposed between the upper panel and the lower panel. Data voltages and a common voltage are respectively applied to the pixel electrodes and the common electrode to generate electric fields, which determine orientations of liquid crystal molecules in the liquid crystal layer. The orientations of the liquid crystal molecules in turn determine transmittance of light passing through the liquid crystal layer and a desired image is displayed by controlling the voltages applied to the electrodes.
A polarity of a data voltage applied to a pixel is reversed between adjacent two frames. In addition, the data voltages in a frame for the different pixels do not have the same polarity. This technique of differentiating the polarity of the data voltages for the pixels is called inversion, and the types of the inversion include column inversion, one-dot inversion, double-dot inversion and so on.
The column inversion reverses the polarity of the data voltages for adjacent pixel columns. The one dot inversion and the double-dot inversion perform a line inversion as well as the column inversion. The one-dot inversion reverses the polarity of the data voltages for the pixels connected to a current gate line with respect to that for the pixels connected to a previous gate line. The two-dot inversion reverses the polarity of the data voltages for the pixels connected to the current two gate lines with respect to that for the pixels connected to the previous two gate lines.
When an image displayed on a screen has a pattern like the one-dot inversion and the column inversion, flicker is generated on the screen. The flicker is resulted from the difference in luminance of the pixels supplied with the data voltages with opposite polarities.